The present invention relates to an image output apparatus for outputting an image on a photosensitive recording medium using mask members formed by color separation, and more particularly to a color image recording apparatus which is to be used in combination with a monochromatic printer for producing a color image.
Conventional image recording apparatus are classified into electrophotographic recording apparatus, ink-jet recording apparatus, thermal transfer recording apparatus, and other recording apparatus. In these recording apparatus, a color image is reproduced and recorded on a sheet of paper, for example, based on color image information.
Image recording apparatus employing a photosensitive pressure-sensitive sheet of paper as a photosensitive recording medium have been proposed in order to solve the problems of the high price of an electrophoto-graphic copying apparatus, the high running cost of such an apparatus due to the maintenance of a photosensitive body and other parts, or the long period of time required to produce photoprints in a silver salt photographic system. In the image recording apparatus, mask members are first produced which monochromatically record images thereon based on red, green, an blue image information which has been supplied as input signals from an image scanner or the like. Then, the photosensitive pressure-sensitive sheet is exposed to light successively through the mask members. After the exposure, the photosensitive pressure-sensitive sheet is pressed to fix a color image thereon. The contrast of the output image can be adjusted by adjusting the amount of light to which the mask members are exposed.
One known color image recording apparatus employing mask members will be described in more detail with reference to FIG. 1 of the accompanying drawings. The recording apparatus has a mask member generators 41 for generating mask members and a color image recorder 42. The mask member generator 41 comprises a laser printer of the electrophotographic type. The mask member generator 41 has a polygonal scanner 2, a photosensitive body 3, an image developing unit 4, a sheet feed cassette 5, and an image fixing unit 6. The color images recorder 62 has an exposure light source 21, an intermediate sheet 22, an intermediate sheet discharge tray 23, a photosensitive pressure-sensitive sheet 24 of paper, a color image sheet discharge tray 25, a thermal fixing unit 26, a color developer sheet cassette 27, a pressure developing unit 28, an intermediate sheet resist roll 31, and an intermediate sheet positioning device 32.
The polygonal scanner 2 applies a laser beam to the photosensitive body 3 that has been charged, for thereby forming an electrostatic latent image thereon. The electrostatic latent image on the photosensitive body 3 is then developed into a visible toner image by the image developing unit 4, and the toner image is thereafter transferred onto a sheet of plain paper or an OHP sheet which is supplied from the sheet feed cassette 5. The toner image is then fixed to the sheet by the image fixing unit 6.
For recording a color image on a sheet using the color image recording apparatus which employs mask members, the color image recording apparatus as shown in FIG. 1 must be purchased even if the user has already had a monochromatic recording apparatus capable of forming mask members. Mask members which are employed in the color image recording apparatus can easily be produced by a monochromatic recording apparatus, which can also produce black-and-white images.
Demands for reproduction of color images are not so often in normal usage of the apparatus. Therefore, the purchase of such two different recording apparatus may be too costly, and require a large installation space.
More specifically, many laser printers for producing monochromatic hard copies have already been available in the market. Therefore, in the event that the user already has such a laser printer, the purchase of a color image recording apparatus which is also capable of producing monochromatic images, in order to obtain color images, would result in the possesion of two monochromatic printers, which would be a waste of money and space.
Co-pending U.S. patent application Ser. No. 50,313 has been filed on May 14, 1987. Other co-pending U.S. patent applications have been filed on February 23, 1988 (U.S. Ser. No. 159,296), and on March 25, 1988 (U.S. Ser. No. 173,610).